1. Field of the Invention
The present invention relates to a printing apparatus which, in accordance with a reprint instruction, is capable of reprinting print data that has been printed once, and to a method of controlling this apparatus.
2. Description of the Related Art
There is user demand for the ability to print a certain document again after this document has already been printed. Japanese Patent Laid-Open No. 2001-063158 discloses a reprint technique for meeting this demand by reprinting a document in accordance with a reprint instruction, which is entered by performing an operation at the panel of an image forming apparatus, without re-transmitting the print data from a data processing apparatus to the image forming apparatus.
In ordinary print processing, an image forming apparatus stores a print job, which has been received from a data processing apparatus, in a storage device of the image forming apparatus, and deletes the stored print job after the job has undergone print processing.
In a reprint mode in which reprinting is possible, on the other hand, the image forming apparatus does not delete the stored print job, even after print processing has ended, and continues to store the print job to be reprinted until there is no longer space available in the storage device of the image forming apparatus. This means that an image once printed can be printed again in response to a reprint instruction performed by panel operation without print data being received from the data processing apparatus again.
In another proposal, the image forming apparatus in the reprint mode stores received print jobs automatically in a job spool area within the storage device. The image forming apparatus stores image data, which is the result of rendering an automatically stored print job, in the image spool area of the storage device. The image forming apparatus uses this stored image data when reprinting is performed, thereby shortening the time from start to end of printing. Japanese Patent Laid-Open No. 2009-122928 describes the storage not only of PDL data of a print job but also of a predetermined number of pages as image data obtained by rendering PDL data, and the execution of printing by using this image data when reprinting is performed.
The techniques mentioned above have the following problems: First, the storage area for print data capable of being stored in the storage device is limited. When a print job having a large number of pages overall is stored, the storage capacity of the storage device comes under pressure.
Second, even a print job that does not require very much time for rendering of PDL data to image data is stored in the storage device as image data. As a consequence, regardless of the fact that the image data is stored using the precious memory area of the storage device, a significant increase in speed at reprint time cannot be expected.